For this two-year study, we propose exploratory research to develop interventions to address the multifactorial geriatric syndrome of delirium at discharge in older persons. Delirium is well-documented to represent a common, serious, and preventable problem in older hospitalized persons; yet previous work has emphasized its transient nature. Recent studies and our preliminary work document that approximately 50% of delirium persists to the time of hospital discharge and often for months beyond. Since risk factors for delirium at discharge have not been previously addressed, this proposal is novel both in its subject matter and in the intervention strategy that will result. Overall objectives are: (1) to develop and validate a predictive model for delirium at discharge in hospitalized older patients; and (2) to pilot-test interventions targeted towards the identified risk factors. We propose a prospective validation study in which the predictive model will be developed based on risk factors identified in an initial cohort of 525 patients, with subsequent validation of the model in a separate test cohort of 469 patients. This study will involve analysis of previously collected data from these two cohorts. Delirium at discharge will be defined as delirium developing during hospitalization that is still present at hospital discharge. Our goal is to identify independent risk factors associated with delirium at discharge using multivariate continuation ratio models. Our underlying hypothesis is that these risk factors will include factors related to the baseline vulnerability of the patient, the type and severity of precipitating factors, and characteristics of the delirium itself (i.e., type, severity). Once risk factors are identified, we will develop and pilot-test intervention protocols targeted towards them in a newly enrolled sample of 75-100 hospitalized older patients with delirium. Our goal is to develop standardized protocols, and pilot-test them for feasibility, acceptability, effectiveness, and reproducibility. Strengths of the proposed study include its innovation in addressing a novel area of investigation- delirium at discharge-applying innovative, state-of-the-art biostatistical and validation methods. Other strengths include substantial preliminary work, clinically rich databases, experience of the research team, and supportive research environment. Thus, this study is highly significant for the promise it holds to increase our understanding of delirium at discharge - a common, morbid condition for older persons- and to facilitate development of a novel intervention strategy to prevent this problem.